Delayed puberty and growth are well documented sequelae of sickle cell anemia. Girls with sickle cell disease, for example, begin their menses 2 to 3 years later than the general population. Various endocrinologic mechanisms for this delay have been proposed; however, few clinical investigations have been performed. In 1975, Olambiwonnu et al. demonstrated, using available assays, that certain pituitary hormone levels in prepubertal children with sickle cell disease are elevated. This suggested that sexual development is delayed as a result of impaired ovarian or testicular function. However, their study did not evaluate other hormones, nor could it take advantage of the improved sensitivity of laboratory assays available today. No more recent studies have been published. The plan of this study is to do a more comprehensive study of sexual maturation in children with sickle cell disease. It is hoped that investigating an etiology for pubertal delay in these children will advance understanding and may assist in the care and treatment of adolescents with sickle cell disease.